TY - JOUR

T1 - Flow modeling in Pelton turbines by an accurate Eulerian and a fast Lagrangian evaluation method

AU - Panagiotopoulos, Alexandros

AU - Zidonis, Audrius

AU - Aggidis, George

AU - Anagnostopoulos, Ioannis

AU - Papantonis, Dimitris

N1 - Copyright © 2015 A. Panagiotopoulos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PY - 2015

Y1 - 2015

N2 - The recent development of Computational Fluids Dynamics (CFD) has allowed the flow modeling in impulse hydro turbines that includes complex phenomena like free surface flow, multi fluid interaction, and unsteady, time dependent flow. Some commercial and open-source CFD codes, which implement Eulerian solving methods, have been validated against experimental results showing satisfactory accuracy. Nevertheless, further improvement of the flow analysis accuracy is still a challenge, while the computational cost is very high and unaffordable for multi-parametric design optimization of the turbine’s runner. In the present work, a CFD Eulerian approach is applied at first, in order to simulate the flow in the runner of a Pelton turbine model installed at the laboratory. Then, a particulate method, the Fast Lagrangian Simulation (FLS), is used for the same case, which is much faster than the Eulerian approach, and hence potentially suitable for numerical design optimization, providing that it can achieve adequate accuracy. The results of both methods for various operation conditions of the turbine, as also for modified runner and bucket designs, are presented and discussed in the paper. In all examined cases the FLS method shows very good accuracy in predicting the hydraulic efficiency of the runner, although the computed flow evolution and torque curve during the jet-runner interaction exhibit some systematic differences from the Eulerian results.

AB - The recent development of Computational Fluids Dynamics (CFD) has allowed the flow modeling in impulse hydro turbines that includes complex phenomena like free surface flow, multi fluid interaction, and unsteady, time dependent flow. Some commercial and open-source CFD codes, which implement Eulerian solving methods, have been validated against experimental results showing satisfactory accuracy. Nevertheless, further improvement of the flow analysis accuracy is still a challenge, while the computational cost is very high and unaffordable for multi-parametric design optimization of the turbine’s runner. In the present work, a CFD Eulerian approach is applied at first, in order to simulate the flow in the runner of a Pelton turbine model installed at the laboratory. Then, a particulate method, the Fast Lagrangian Simulation (FLS), is used for the same case, which is much faster than the Eulerian approach, and hence potentially suitable for numerical design optimization, providing that it can achieve adequate accuracy. The results of both methods for various operation conditions of the turbine, as also for modified runner and bucket designs, are presented and discussed in the paper. In all examined cases the FLS method shows very good accuracy in predicting the hydraulic efficiency of the runner, although the computed flow evolution and torque curve during the jet-runner interaction exhibit some systematic differences from the Eulerian results.

KW - Pelton hydro turbines

KW - Jet-runner interaction

KW - CFD

KW - Eulerian modeling

KW - Fast Lagrangian Simulation

KW - Design optimization

U2 - 10.1155/2015/679576

DO - 10.1155/2015/679576

M3 - Journal article

JO - International Journal of Rotating Machinery

JF - International Journal of Rotating Machinery

SN - 1023-621X

M1 - 679576

ER -